The present application claims priority to European Patent Application No. 05425776.1, filed Nov. 4, 2005, which is incorporated by reference herein in its entirety.
The present invention relates to a fast-fit coupling for a fluid circulation system.
There are known fast-fit couplings adapted to provide the fluid connection between two or more fluid conveying pipes, while allowing the fast insertion/disconnection of each pipe in the coupling itself.
In greater detail, the coupling comprises a receiving body defining a plurality of conduits adapted to be engaged by respective fluid conveying pipes and a plurality of openings adapted to allow the insertion/disconnection of each pipe inside a respective conduit.
The coupling also comprises, for each conduit, a fastening ring provided with a plurality of fins adapted to be shifted from the relative position according to an insertion direction of the pipe itself so as to prevent the further advancement of the pipe itself, a sealing ring adapted to fluid-tightly abut against a side surface of the respective pipe so as to prevent the leakage of fluid, and a sliding locking member inside the body and adapted to cooperate with the pipe on the part opposite to the fastening ring to lock the respective pipe in a predetermined position. More precisely, the locking member is available in a first operative position, in which it locks the pipe on the opposite side of the fastening ring preventing the pipe to be disconnected in the opposite direction to the connection direction, and in a second operative position, in which it does not withhold the pipe on the side opposite to the fins allowing the pipe to be disconnected from the conduit.
In particular, each locking member is placed adjacent to the respective opening and each fastening ring is interposed between the sealing ring and the locking member.
During insertion of each pipe, the locking member is available in the first operative position, and each pipe is inserted in the respective coupling body so as to determine the sliding of the pipe itself firstly on the respective fastening ring and then on the sealing ring to reach the predetermined locking position.
The disconnection of each pipe from the respective conduit occurs by bringing the locking member to the second operative position and pulling out, through the respective aperture, the pipe along with the sealing ring and the locking ring.
The couplings of the known type provide a suboptimal fluid tightness, in particular when the pipes are made of plastic material. More precisely, the sliding of the side surface of the pipes on the fastening ring scratches the side surface and alters its shape. As a result, the fins on the sealing ring do not fluid-tightly abut against the side surface of the respective pipe and, therefore, spillage and/or leakage of fluid may occur.
In order to remove such drawback, couplings in which the sealing ring and the fastening ring present exchanged positions along the insertion/disconnection direction of the pipe are known. In this way, during insertion of each pipe, the respective side surface slides firstly on the sealing ring and then on the fastening ring; therefore, the fluid tightness provided by the coupling is optimal because the possible scratches on the side surface generated by the relative sliding between pipe and fins do not cooperate with the sealing ring.
Such couplings are available in a first embodiment in which each locking member is fastened to the body of the coupling so as to lock, on opposite side of the respective fastening ring, the respective pipe in the predetermined locking position. Such first embodiment presents the drawback of not allowing the pipes to be disconnected from the respective conduits.
In a second embodiment, each locking member is releasably constrained to the coupling body so as to be available in a first operative position, in which it locks the respective pipe in the predetermined locking position, and in a second operative position, in which it does not withhold the pipe in the predetermined locking position allowing the pipe itself to be disconnected.
Each locking member is moved between the first and the second operative positions by means of a threaded connection arranged between each locking member and the coupling body.
Operating the threaded connection requires the relative rotation of the releasing member with respect to the coupling itself according to a predetermined number of turns. Therefore, the disconnection of each pipe from the respective conduit is awkward in difficulty accessible spaces.